track-4-ben-verhagen - validation of asme 31g and rstreng

VALIDATON OF THE ASME B31G AND RSTRENG

METHODOLOGIES FOR THE DETERMINATION OF THE

BURST PRESSURE OF CORRODED PIPES IN API 5L X70 / EN

10208-2 L485

Frédéric Dewint, AIBFrédéric Dewint, AIB--Vinçotte InternationalVinçotte International

33rdrd ASME India Oil & Gas Pipeline Conference, 2011, February 3ASME India Oil & Gas Pipeline Conference, 2011, February 3--5, Goa, India5, Goa, India

CONTENTS

• OBJECTIVES OF THE STUDY

• FAILURE PRESSURE ACCORDING ASME B31G AND RSTRENG

• TEST PROGRAM

- Burst tests

- Strain gauge measurements

- Calculations in accordance with ASME B31G and RSTRENG

- Linear and Nonlinear Finite Element Calculations

• CONCLUSIONS

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

REMARK

The study was performed in collaboration between

AIB-Vinçotte International (www.vincotte.com)

Fluxys (www.fluxys.com)

Labo Soete of the Ghent University (www.tribology-fatigue.ugent.be)

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

OBJECTIVES OF THE STUDY

• Validate ASME B31G and RSTRENG methodologies on pipe in X70 / L485 material with supplementary requirements related to :

- ratio yield strength / tensile strength

- impact testing at –20°C

• Demonstrate the real safety margin of corroded high pressure gaspipelines in X70 / L485 against bursting under internal pressureloading.

• Assess the capability of Finite Element calculations for predicting the failure pressure of corroded pipes and in a further step thefailure pressure of corroded fitings.

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

ASME B31G & RSTRENG

• The ASME B31G and RSTRENG methodologies are used for the determination of the remaining strength of externally corroded pipe subjected to internal pressure loading.

• Both methodologies modelize defects by their depth d and by their length L in the longitudinal direction. The defect width w is not considered explicitly in the calculation.

• RSTRENG allows to take into account more accurately the corrosion defect geometry.

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

LIMITATIONS

• Limited to corrosion on weldable pipeline steels categorized as carbon steels or high strength low alloy steels.

• Do not apply to welds except to corrosion anomalies in submerged arc seam welds.

• Defects caused by mechanical damage, such as gouges and grooves, are prohibited.

• Limited to anomalies having depths lower than 80 percent of the wall thickness.

• Limited to defects which have relatively smooth contours and cause low stress concentrations (e.g. electrolytic or galvanic corrosion, loss of wall thickness due to erosion).

• Only internal pressure loading is considered.

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

ASME B31G CALCULATION METHOD

failure pressure is Pfail = 2 x Sfail x t / D with :

D : diameter of the pipe

t : wall thickness of the pipe

Sfail : failure stress = S (1-A/Ao)/[1-(A/Ao)(MT-1)]

S : flow stress = 1.1 SMYS

A : defect area in the longitudinal plane through the wall thickness ; B31G considers A = (2/3) d L

Ao : is L t

MT : two-term Folias factor ; f(L, Dt)

L : axial extent of the defect

d : maximum defect depth

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

RSTRENG CALCULATION METHOD

failure pressure is Pfail = 2 x Sfail x t / D with :

D : diameter of the pipe

t : wall thickness of the pipe

Sfail : failure stress = S (1-A/Ao)/[1-(A/Ao)(MT-1)]

S : flow stress = SMYS + 10 ksi = SMYS + 69 MPa

A : defect area in the longitudinal plane through the wall thickness ; if no detailed analysis, i.e. : 0.85 d L

Ao : is L t

MT : three-term Folias factor ; f(L, Dt)

L : axial extent of the defect

d : maximum defect depth

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TEST PROGRAM

• To demonstrate the validity of the ASME B31G and RSTRENG methodologies for pipe material X70/L485, a test program was defined by Vinçotte in collaboration with Fluxys and the Laboratory Soete of Ghent University :

- burst testing of the test pieces with artificial defects

- comparison with failure pressure from ASME B31G & RSTRENG

- comparison with failure pressure calculated by finite element method

- comparison of strain gauge measurements with the strains from finite element calculations

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

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TEST PIECE PARAMETERS

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

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TEST PIECE 4 drawing

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

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Strain gauges installation

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

Strain gauges installation

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TEST PIECE 1 tensile test results

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TEST PIECE 1 impact test results – 2 o’ clock

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

3D model

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP1 : DN600 tactual = 11.3 mm Pdesign = 80 bar

Defect 3 : L = 210 mm d = 4.1 mm w = 100* mm

Actual Burst Pressure : 214 Bar

ASME B31G : 166 bar RSTRENG : 164 bar FEM-NL : 175 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP2 : DN600 tactual = 11.4 mm Pdesign = 80 bar

Defect 2 : L = 200 mm d = 6.8 mm w = 128 mm

Actual Burst Pressure : 150 bar

ASME B31G : 143 bar RSTRENG : 133 bar FEM-NL : 83 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP3 : DN900 tactual = 13.4 mm Pdesign = 84 bar

Defect 2 : L = 300 mm d = 4.0 mm w = 200 mm

Actual Burst Pressure : 173 bar

ASME B31G : 134 bar RSTRENG : 134 bar FEM-NL : 125 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP4 : DN900 tactual = 13.4 mm Pdesign = 84 bar

Defect 1 : L = 300 mm d = 6.0 mm w = 600 mm

Actual Burst Pressure : 133 bar

ASME B31G : 122 bar RSTRENG : 118 bar FEM-NL : 97 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

RESULTS

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

Strain Gauge Measurement Results

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

Comparison strain gauge measurements / FEM

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

Test Piece 2 - defect 1 / Von Mises stresses

TP4 defect 1 - Von Mises strain : max. 1.1% at 75 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP4 defect 1 - Von Mises strain : max. 1.8% at 82.5 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP4 defect 1 - Von Mises strain : max. 3.2% at 90 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP4 defect 1 - Von Mises strain : max. 5.1% at 97.5 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

TP4 defect 1 - Von Mises strain : max. 23 % at 105 bar

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485

CONCLUSIONS

• The failure pressures calculated with ASME B31G and RSTRENG method are conservative values compared with the actual bursting pressure values.

• The failure pressures calculated with the nonlinear FEM method are conservative values compared with the actual bursting pressure values.

• The failure pressures calculated with the linear FEM method are too conservative in order to be useful for practice.

• The correspondence between the strain gauge measurements and the FEM calculated strains was good in the range were measurements were possible.

• Corroded pipe in X70 / L485, as ordered in Belgian practice, has large safety margin against bursting under internal pressure.

Questions & Answers

VALIDATION OF THE ASME B31G AND THE RSTRENG VALIDATION OF THE ASME B31G AND THE RSTRENG

METHODOLOGIES FOR PIPE MATERIAL X70 / L485METHODOLOGIES FOR PIPE MATERIAL X70 / L485